I haven't used mine because I have never needed to, but a friend with whom I RV has used his many times. Although actually his non-Chinook rig did not come with self-jump-start ability, but only a combiner that could be used for charging while underway. However, he carried jumper cables, and could thus reach from his house bank to his start battery and self-jump start that way. He had a combination of some parasitic drain that was causing his start battery to run down, plus an overly small start battery (since fixed). Since he still wanted the ability to connect start and house banks (albeit used very infrequently), when we re-did his electrical, we put in a thicker wire, with fusing at both ends and a manual switch in between (taking the place of the combiner). The wire is stout enough that it can be fused with large enough fuses to allow self-jump-starting, thus the switch can be used for that as well as combining with no "extra" parts.
Even though we both carry lithium jump packs, I can still see a use for the self-jump start. For one thing, it's fast and can be done from the driver's seat. That could be handy in certain situations. And you can't forget to charge it up (as with the lithium packs which can run down in storage). Also, as mentioned above, if you have charge combining ability, you are most of the way there (although the fusing has to be slightly higher, but you'd want that larger wire to combat voltage drop anyway).
I like both. I would consider not carrying jumper cables first (of the trio of self jump, battery pack, and jumper cables) because they require a second vehicle. I like the lithium pack because it's small, has multiple uses, and I can help someone else out without moving my rig or involving it in any way (have done that a few times). And I have the self-jump setup wired in place. Hence the jumper cables would be the first to go if one had to go. But I do carry all three now.
Thus I were re-doing (again), for me to eliminate the self-jump ability, I'd also "need" to eliminate the start/house combiner cable (because if I didn't, there is no reason to eliminate self jump ability). Well, I will say that I almost never combine (because my solar charger is ten times smarter and better than an alternator for charging the house bank; the shore charger would be too if I ever used it), and I have never self-jump started. So based on that maybe I could eliminate the whole works (which would eliminate a long 1/0 cable, a fuse, and a switch*). BUT, one, I already have it in place, and I'm not THAT weight constrained. And I have used the combine feature a couple of times. And the self-jump feature is automatically included since it uses the same switch/wire/fuse as the combiner.
(If only interested in actual thread topic, you can stop reading now...
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BUT....I won't be doing that (eliminating the combine wire), because I have a dastardly plan. It's not likely to appeal to very many people, but just to put my comment in context I'll mention it. See, I have not once used my generator. So I lug it around in what could be good storage space. But I HAVE used a camping buddy's generator (so it could have been mine) for precisely three purposes:
1) Electric heat gun when doing electrical work (I have tried many non-electric types but have never found a satisfactory one).
2) Vacuum cleaner (I can use 18v batteries, but it's great to just plug it in and let 'er rip). This one will mostly go away when I remove the carpeting (O' Happy Day), but not completely.
3) One or two power tools that I don't have battery versions of and/or the battery versions don't work as well (router, buffer, Multi-Master).
As you can see, these are all very occasional uses. The heat gun work I could just take a campground site and plug in, but the power tools make noise so that's a great time to be boondocking (miles away from people so no-one is bothered). I have removed the rooftop air-conditioner, the microwave, and the electric coffee maker as these are not things I use.
So I noodled options. And I have come up with one that I think will work great for me, and thus I will remove/sell the generator this winter (which has all of about 21 hours on it, none of them put on by me actually needing a generator). I tested my plan by trying it out on a friend's rig who had all of the components in place so that I could measure things.
My plan is to install either a 1000 or 1500 watt inverter. Except for the above scenarios, I won't be using it, because I don't really have much that draws 110 on a regular basis, and the small things I do have (toothbrush charger, for example) will easily run from a plug-in-to-cigarette-lighter 75 watt inverter. So why put it in? Specifically to run the heat gun, vacuum, and power tools. Will my battery bank support much of that large a draw? Yes, for short runs, but I don't plan for it to. My plan (and this is what I tested on my buddy's rig, which is set up basically just like mine but with a 2000 watt inverter) is to simply run the engine - in combine mode - for those short periods of time when I have the inverter/tools on. I did this on my friend's rig by using the exact tools I plan to use, his 2000 watt inverter, and his battery meters (he also has the V10 with the same alternator we do).
I was able to see that the majority of the power that the inverter was drawing came "straight from" the alternator/combiner line. My batteries thus will barely have to lift a finger. So, for my limited and occasional uses, this should work out just fine and makes more sense to me than carrying around a two-hundred pound gasoline generator. Side bonus is the inverter won't "mind" if I don't use it for a year, whereas the generator likes to be exercised, needs maintenance, etc.
I know this wouldn't suit most folks, so I'm not suggesting it by any means. But for me I think it will work just fine, and that's one reason I will be keeping the combiner line (1/0 wire from start batt to house bank). And since I have the combiner line, it works as a self-jump start mechanism without adding or changing anything.
BG
*In case it wasn't clear above, the standard system that came on my Chinook is not what I have now. My rig (and likely many other Chinooks) had a 4AWG wire running from start battery to house bank, through a Sure-Power combiner. This included an off-shoot wire, from the combiner, that ran to a "self jump start" switch on the overhead by the driver. An issue with this system was that the wire wasn't properly fused at both ends (I don't think it could have been, due to a combination of smaller wire and large current). I removed that and put in larger, 1/0 wire, with a fuse at both ends. In the place of the combiner, I put a manual switch. But that's only because I rarely use it. If I had wanted to, I could have put in a combiner instead of the switch. I would have used a Blue Sea 7622. The 7622 includes a switch that can be used for self-jump-starting (that is, it lets you choose to combine at your will, which is all self-jump-starting really is).
PS: I could have used self-jump-start once on my previous camper van. Just after I bought it, I stopped at a rest area to sack out (super tired after a marathon drive in a rental car to pick up said camper van) and forgot the lights on. Woke up, went to start, and .... dead battery
That rig had no self-jump-start feature on the combiner, and I had no battery pack (they hadn't come along yet) and no jumper cables (see: drove rental car to pick up camper van. Luckily, I was only about an hour from the seller's house, and he came out and gave me a jump start (whew).
